1. Field of the Invention
The present invention is directed to a circuit for compensating fluctuations of mains voltage and load voltage at a user and, in particular, to such a stabilization for users with anticipated, definable fluctuations in load voltage.
2. Description of the Prior Art
Electronic devices are usually very sensitive to voltage fluctuations in the supply network. In the case of a gradient amplifier in medical technology, for example, voltage fluctuations can distort the current pulses emitted by the amplifier, and thus falsify measured results.
Voltage fluctuations are partly caused by load fluctuations of the devices themselves. Dependent on the measurement sequence, thus, a gradient amplifier at different times represents very different loads for its power supply that can cause voltage fluctuations.
Fluctuations in the network can be intercepted by means of a preceding, interruption-free power supply (USV) or by switching transformer windings of the power pack device. Fluctuations in load voltage as occur in a gradient amplifier are alleviated by an electronic power pack or by an over-dimensioned transformer circuit of the device to be stabilized. A collapse of the secondary voltage of the transformer of the device to be stabilized due to a load, however, is usually not compensated.
U.S. Pat. No. 5,610,501 discloses a power flow regulator for a transmission line. The power flow regulator is thereby connected to the transmission line via a shunt transformer and a series transformer and has a rectifier circuit that is supplied by the shunt transformer and comprises an inverter (A.C. converter) supplied by the rectifier circuit that injects an alternating voltage, via the series transformer, that has a controllable amplitude and phase angle with respect to the phase of the transmission line.